Sealing device for pivotal joints



Nov. 27, 1945. A. SEARLES ETAL SEALING DEVICE FOR PIVOTAL 'JOINTS 3 Sheets-Sheet 1 Filed Oct. 22 1941 INVENTORS AT TORNE Y5 3) Amos Sear/es and 1 Char/e5 AJM/arfz B) M q M 0 w M W w W A z Z l 1 Z 7 m A i|1|||/ m M mo A WW1PV 7 4 V m 9 4 Fig .3.

Nov. 27, 9 A. sEARLEs ETAL 2,389,874

SEALING DEVICE FOR PIVOTAL JOINTS s Sheets-Sheet 2' Filed Oct. 22, l94l IINVENTORS Amos Sear/es and Char/es A. 84/67/72 5) M QL'W nun!" ATTOKNE Y5 Nov. 27, 1945. A. SEARLES ET AL SEALING DEVICE FOR PIVOTAL JOINTS Filed Oct. 22, 1941 v 3 Sheets-Sheet 3 INVENTORS Amos Sear/e5 and Chair/e5 A. Swan? AT TORNEYS Patented Nov. 27, 1945 2,389,874 SEALING DEVICE FOR PIVOTAL JOINTS I Amos Searles, Moscow, Pa., and Charles A. Swartz, Yonkers, N. Y.

Application October 22, 1941, Serial No. 416,028

16 Claims. This invention relates to sealing devices and it is an important object of the invention to provide a sealing device which effectively prevents the intrusion of foreign particles such as grit, sand or other particles of fine abrasive-material between the surface of the two cylindrical cooperating bearing members formed of rigid material and one of which is adapted to oscillate back and forth through an angle usually less than 360 degrees with reference to the other. The sealing of such bearing members by means of a device constructed in accordance with the present invention prevents the rapid wearing away of their bearing surfaces which would be caused by particles of foreign abrasive material collecting therebetween.

Such cooperating bearing members are commonly found in chains of the conveying and power transmitting types in which the successive links of the chain are connected together by means of shafts or pins on which certain of the links oscillate back and forth to a limited degree with reference to the next succeeding links. The links of such a chain oscillate through a substan'tial angle when they are passing over the teeth of the driving, driven or idle sprockets,

Such conveyor chains often carry small buckets which dip into and elevate sand. or similar fine gritty and abrasive material from a pile of such material. It has been the practice in the construction of such conveyor chains to attempt to prevent the intrusion of the sand or other particles of the material being elevated into the bearlng surfaces at the pivotal joints of the chain by making the working clearances between the links and bearings at the pivotal joints of the chain as small as feasible.- Even when the clearances have been kept to a minimum, however, it has been found that the bearing surfaces of the chain were subjected to rapid wear and deterioration due to the intrusion of the sand or other material between the bearing surfaces. This wear of the bearing surfaces rapidly reduced the useful life of the chain as a Whole and after a rather short period of use, such chains have been rendered useless due chiefly to the increase in pitch or distance between the centers of their pivotal connecting pins which cause the chain to climb the sprocket teeth and become disengaged therefrom, thus rendering it inoperable.

It is an object of this invention to protect the pivotal bearing surfaces of such chain against wear by providingsealing devices arranged to prevent the entrance of particles of sand or other foreign material to such bearing surfaces during the operation of the chain.

. It is a further object of the invention to provide a, sealing device for the bearing surfaces of relatively oscillatable members in which the sealing device comprises a member formed of resilient material such as rubber.or synthetic rubber and in which spaced apart portions of the resilient member are compressed into such firm gripping relation with the two oscillatable members that no slippage takes place between the contacting surfaces of the oscillatable members and the re silient member. The seal is in the nature of a diaphragm for preventing the entrance of particles of abrasive material to the bearing surfaces.

Still another object of the invention is the provision of a. sealing devic for bearing surfaces which is composed of few parts, is simple and inexpensive to construct and is not subject to rapid wearing away but has a long life even in the presence of sand or similar gritty material.

For a better understanding of the invention, reference ismade to the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a sectional view showing a sealing device according to the invention as applied to the connecting links of a power or conveyor chain before the outer links of the chain are drawn together close to their companion center link; Fig. 2 is a sectional view similar to Fig. 1 showing the sealing device thereof in position after the outer chain links have been adjusted inwardly into their proper operating position;

Fig. 3 is a front view on a smaller scale showing several connected links of a chain having links of the type shown in Fig. 1;

Figs. 4 and 5 are sectional views showing portions of a. chain and sealing device and illustrating modified forms of the invention;

Fig. 6 is a sectional view of a, resilient sealin device embodyin the invention;

Fig. 7 is an end view of the device shown in Fig. 6 partly broken away; and

Fig. 8 is a sectional view of a modified form of sealing device generally similar to that shownin Fig. 6.

Referring first to Figs. 1. to 3 of the drawings, the invention is shown in connection with a portion of a power or conveyor chain consisting of pairs of outer links l.2 which are connected together by means of the center links and the pivotal connections to be described. The link 3 at each of its opposite ends is provided with a cylindrical bore t adapted to pivotally and snugly receive the cylindrical bearing surface I provided on an elongated bushing 8. The bushing 8 is providedlat its opposite ends with portions I and 8 of reduced diameter adapted to receive correspondingly sized bores 9 and i provided in the links I and 2. Means are provided to draw the links I and 2 up against a pair of shoulders i i and I2 provided on the sleeve or bushing 8. Such means comprise a bolt is having one end threaded, as at M, to receive a nut l5 and its opposite end tapered to enter a correspondingly tapered bore l8 provided in a washer l1, the latter end of the bolt l8 also being provided with a slot l8 adapted to receive a screw driver or similar tool. A second washer I9 is mounted on the bolt 13 and adapted to be slid therealong by the nut l5. For the purpose of sealing the bearing surface 5 against the admission of foreign particles thereto, a pair of similar sealing devices A and B are provided as shown. The center link 3 is provided with a pair of annular grooves 20, 2i and the outer links i2 provided with the registering grooves 22, 23 respectively, so that the links i and 8 together form a housing in which the sealing member A is seated while the links 2 and 3 together form a housing in which the sealing member B is seated.

Referring to Figs. 6 and '1, the sealing member A is formed of a length of tubing 24 which may be natural rubber or any one of the known synthetic rubbers and when the term rubber is hereafter used in the specification or claims it will be understood as referring to natural rubber or any one of the known synthetic rubbers. The tube 24 is bent or folded over to provide reverted end portions 25, 28 which are folded over a pair of metallic rings 21, 28 which are spaced slightly apart. After the ends 25-28 of the rubber tube 24 are folded over they may be cured by suitable heat treament or vulcanized to set them into permanent shape so as to retain the rings 21-28 in place. Or the ends 25-26 may for a short distance from their inner edges be vulcanized to the peripheral surfaces of the rings 21-28, so that the metallic rings become firmly united to the outer ends of the tube. As shown, the inner surfaces of the rings are cut away. as indicated at 29, to clear the horizontal central portion 80 of the tube 24 which connects together the end portions 25-26.

Referring to Figs. 1 and 2, the outer diameters of the grooves 20-22 and 2i-23 are somewhat smaller than the outer diameter of the sealing members A and B so that when the sealing members are inserted in such grooves by assembly into the position shown in Fig. 1, the rubber in the end portions 25 and 26 of the sealing members becomes compressed and is biased outwardly by the rings 21-28 into firm engagement with the peripheral surfaces of the respective grooves. As the nut I5 is further tightened to complete the assembly operation, the extreme ends of the sealing members A and B are engaged by the chain links and become compressed somewhat so that the horizontal portion 30 of the tubing becomes slightly thicker under the action of compression as indicated in Fig. 2. The nut I5 is tightened until the parts are in the position shown in Fig. 2 when the links I and 2 come into firm engagement with the shoulder H and I2 respectively so that the bushing 6 and links I and 2 are firmly secured together as a unit. The thickness of the link 3 is slightly less than the distance between the shoulders li -l2 of the bushing 6 so that the link 3 is pivotally mounted assas'rs and free to oscillate on the bearing surface 5 of the bushing 8 as the chain passes over a sprocket. While the provision of the shoulders li-i2 on the bushing 8 has been illustrated as the means for locking this bushing to the side links, it will be understood that any known means for locking bearing bushings to the side links of a chain may be used instead.

When used as a power or conveyor chain, as the links thereof pass over a sprocket which serves to drive the chain or an idler sprocket at the end oi the chain, the links 8 oscillate on the bearing surfaces 5 through an angle with reference to the links 1-2, such angle of oscillation depending upon the diameters of the sprocket wheels and may be of the order of 30 or more. Considering the action of the sealing member A as the link 3 moves out of its position in alignment with the link I, by reason of the firm frictional engagement between the outer end 25 of the rubber tube 24 with the outer peripheral wall of the groove 20, the end 25 of the tube and also the metallic ring 21 rotate in unison with the link 3 while the other ring 28 and the end 28 of the rubber tube remain locked with the link I by reason of the firm frictional engagement of the outer end 28 of the tube 24 with the outer peripheral wall of the groove.22. This twisting of the tube 24 induces a torsional stress in the horizontal connecting portion 30 which becomes somewhat elongated under the action of such stress, the elasticity of the rubber permitting such deformation and the clearance space provided by the recesses 29 in the rings 21-28 permitting the free movement of the rubber in the connecting portion 30 which forms a diaphragm joined to the link members.

It will be observed that the sealing members A and B prevent the entrance of particles of sand or other foreign material into the joints between the link 3' and the links i2 thus effectively preventing the entrance of such foreign materials into the pivotal bearing surface 5. Any sand particles entering the small clearance space between the links i and 3 are prevented from entering the joint between ends 25 and 2B of tube 24 and the outer peripheral surfaces of the grooves 28 and 22 since the ends of the rubber tube are pressed firmly into engagement with such surfaces so that it is not possible for particles of fine material to enter therebetween. Any particles of sand which happen to pass down between the ends 25 and 28 of the tube and between the rings 21 and 28 are prevented from entering the joint by the horizontal diaphragm formed by portion 30 of the tube which effectively closes such passage-way. It is also apparent that the horizontal portions 30 of the tubes 24 seal the passageways between the center and outer links against the escape of oil, grease, graphite or other lubricant which may be used to lubricate the bearing surface 5 so that the sealing members serve the double purpose of preventing particles of abrasive material from entering the pivotal joint connection as well as preventing the escape of lubricant therefrom.

The arrangement shown in Fig. 4 is generally similar to that shown in Figs. 1 and 2 but in this case the bushing 6a is of uniform diameter throughout its entire length so that the bearing surface 5a extends the entire length of the bushing 6a. Also the grooves 20a, 2la, 22a and 23a extend inwardly to the bushing 611 as shown, so that the sealing member A is disposed in a housing formed by the links la, 3a and the bushing surfaces encircling the pivotal axis of said members and sealing the joint defined between said surfaces, and a pair of spring rings for anchoring the respective end portions of said sealing member into firm frictional engagement with respective rigid members to prevent slippage between said end portions and said rigid members, said rings being free from clamping engagement with the intermediate section of said sealing member between said end portions to permit free torsion of said intermediate section without hindrance from said rings upon relative pivotal movement of said rigid members.

6. In a device of the class described, two rigid members, a member connecting said rigid members and having a cylindrical bearing surface on which one of said rigid members is pivotally supported for limited oscillatory movement in opposite directions about a neutral position with reference to the other rigid member, said rigid members being provided at their opposed adjacent faces with annular channel-shaped registering recesses disposed entirely radially out; wardly of said cylindrical bearing surface, and means for sealing said bearing surface against the admisison of foreign particles thereinto, said sealing means comprising a sealing member formed of a unitary mass of resilient material retained in said recesses, and means for biassing the end portions of said sealing member into such firm frictional engagement with said rigid members as to prevent slippage between said end portions and rigid members,.whereby the portion of the sealing member intermediate its end portions forms an elongated diaphragm which is placed under torsion upon the oscillation of said one rigid member on said bearing surface while remaining impervious to the passage of particles of foreign material into the bearing surface.

7. In a device of the class described, two rigid members, a member connecting said rigid members and having a cylindrical bearing surface on which one of said rigid members is pivotally sup ported for limited oscillator movement in opposite directions about a neutral position with respect to the other rigid member, said rigid members being provided at their opposed adjacent faces with registering recesses, and means for sealing said bearing surface against the admission of foreign particles thereinto, said sealing means comprising a resilient tube retained in said recesses, said recesses having respective walls on the radially outer side of said tube extending towards each other to enclose at least a portion of the radially outer side of said tube, and means for biassing the end portions of said tube into such firm frictional engagement with said rigid members as to prevent'slippage between said end portions and said rigid members, whereby the portion of the tube intermediate its end portions forms an elongated diaphragm which is placed under torsion upon the oscillation of said one rigid member on said bearing surface while remaining impervious to the passage of particles of foreign material into the bearing surface.

8. In a device of the class described, two rigid members, a member connecting said rigid memeign particles thereinto, said sealing means comprising a. resilient tube in said recesses having turned over end portions, said recesses having respective walls on the radially outer "side of said tube extending towards each other to enclose at least a portion of the radially outer side of said tube, and means for biasing said= turned over end portions of the resilient tube into such firm frictional engagement with the walls of said recesses as to prevent slippage between said end portions and rigid members, whereby the portion of the tube intermediate its end portions forms an elongated diaphragm which is placed under torsion upon oscillation of said one rigid member on said bearing surface while remaining impervious to the passage of particles of foreign material into the bearing surface.

9. In a device of the class described, two rigid members provided at their opposed faces with registering recesses, a member connecting said rigid members and having a cylindrical bearing surface on which one of said rigid members is pivotally supported for limited oscillatory movement in opposite directions into a neutral position with reference to the other rigid member, and means for sealing said bearing surface against the admission of foreign particles thereinto, said sealing means comprising a length of resilient tube retained in said recesses, said recesses having respective walls on the radially outer side of said tube extending towards each other to enclose at least a portion of the radially outer side of said tube, and a pair of rings formed of rigid material and secured to said tube at spaced apart regions thereof, said rings biassing the end portions of said tube into such firm frictional engagement with said rigid members as to prevent slippage between said end portions and said rigid members, whereby an axial portion of said tube between the sections where said rings are secured to said tube is permitted to twist torsionally upon relative movement of said rigid members.

10. In a device of the class described, a pair of rigid members, a member connecting said rigid members and having an axial cylindrical bearing surface on which one of said rigid members is pivoted for limited oscillatory angular movement of said rigid members relatively, and means for sealing said bearing surface against the admission of foreign particles thereinto and comprising a tubular resilient sealing member disposed radially outwardly beyond said bearing surface, and extending between the two rigid members axially of said later members, and means for resiliently biasing each end portion of said resilient member into such firm frictional engagement with a corresponding one of said rigid members as to prevent slippage between said end portions and their corresponding rigid members upon normal relative angular movement of said rigid members, the end portions of each of said sealing members in engagement with the rigid members being in substantial axial alignment the intermediate section of said sealing member being substantially cylindrical and free from anchoring attachment to either one of said rigid members to permit said intermediate section to twist torsionally upon said normal relative angular movement.

11. A device as set forth in claim 10, in which the two rigid members form elements of consecutive links of a chain.

12. A device as set forth in claim 10, in which the two rigid members are provided at their opposed faces with registering recesses presenting radially outer axial surfaces, and in which said sealing member is retained in said recesses and has its end portions biassed by said biassing means into frictional engagement with said radially outer axial recess surfaces.

13. A sealing device adapted to seal the bearing surface of a rigid member which is angularly oscillatable in both directions about an axis from a neutral position with reference to a second rigid member disposed alongside of the first member, each of said rigid members presenting an annular surface encircling said axis, the sealing device comprising a tube composed of resilient material, and a pair of coaxial rigid spring rings of the same size biassing the end portions of said tube radially into firm frictional engagement with said surfaces respectively, the intermediate portion of said tube between said end portions being free of initial stress nd free to be distorted torsionally upon relative movement of said rigid members.

14. A sealing device as set forth in claim 13, in which the tube is composed of rubber, and the end portions of the tube are vulcanized to the.

rings respectively.

15. In a device of the class described, two rigid members, a member connecting said rigid members, and having an axial cylindrical bearing surface on which one of said rigid members is pivotally supported for limited oscillatory angular movement in-opposite directions about a neutral position with reference to the other rigid member, said rigid members being provided at their opposed faces with registering recesses which extend radially inwardly to said cylindrical hearing surface, and means for sealing said bearing surface against the admission of foreign particles thereto, said sealing means comprising a, sealing member formed of a, unitarymass of resilient material, and retained in said recesses, said recesses having respective walls on the radially outer side of said sealing member extending towards each other to enclose at least a portion of the radially outer side of said sealing member,

and means for biasing the end portions of said sealing member into such firm frictional engagement with said rigid members as to prevent slippage between said end portions and rigid members, whereby the portion of the sealing member intermediate its end portions forms an elongated diaphragm which is placed under torsion upon the oscillation of said one rigid member on said bearing surface, while remaining impervious to the passage of particles of foreign material into the bearing surface.

16. In a device of the class described, two rigid members, a member connecting said rigid members together and having a cylindrical bearing surface on which one of said members is pivotally supported for limited oscillatory angular movement in opposite directions about a neutral position with reference to the other rigid member and the opposed faces of said rigid members being substantially in overlapping contact with each other and provided with registering recesses, and a sealing member formed of a unitary mass of resilient material and disposed in said recesses whereby said rigid members form a housing about said sealing member, said sealing member extending between said rigid members, and means for biasing the end portions of said sealing member into such firm frictional engagement with said rigid members respectively as to prevent slippage between the said end portions and rigid members upon relative angular movement of said rigid members, the intermediate portion of the sealing member forming a diaphragm effective in preventing the admission of foreign particles into said bearing surface, said intermediate portion being free from anchoring attachment to either one of said rigid members, and being thin enough to permit it to twist torsionally upon relative ngular movement of said rigid members, and to avoid torsional stresses suflicient to create slippage between the biased end portions of the sealing member and said rigid members.

AMOS SEARLES. CHARLES A. SWARTZ. 

